1. Field of the Invention
The present invention relates to a variable magnification finder for use in cameras. More particularly, the invention relates to a finder wherein an objective lens is constructed simply and compactly, by which means a wide angle field of view can be obtained.
2. Description of the Related Art
Conventionally, most compact cameras employ a virtual image finder such as an Albada finder or a reverse Galilean finder. Such finders provide a relatively wide angle of view and have a compact construction because a prism for erecting the image is not required. However, in such finders, the closest lens to an object must be large in size, and the view field of the finder blurs in the marginal zone.
Because of the drawbacks in virtual image finders and continuous requirements to improve compact cameras, cameras may employ a real image finder instead of a virtual image finder. A panorama function is also available in a real image finder.
U.S. Pat. No. 4,842,395 entitled "Finder of Variable Magnification"; Japanese Patent Laid-Open No. SHO 61-156018 entitled "Variable Magnification Finder"; Laid-Open No. PYEONG 6-151197 entitled "Real Image Finder"; and Laid-Open No. 6-18780 entitled "Variable Magnification Finder Optical System" disclose real image finders.
In the disclosed finders, an objective lens group and a condenser lens group form an objective image, and the image is observed through an enlarged eyepiece. However, the image formed by the objective lens group is positioned on the marginal zone of the view field, so that the view field is subject to restriction, i.e., the image is divided by the marginal zone of the view field. When constructing a finder without the division of the image, however, the resultant finder becomes large and complicated.
When a camera is made compact, a moderately wide field of view may be achieved by shortening the focal distance of the objective lens at the wide angle position. However, the image formed through the objective lens is small. Also, the refractive power of the objective lens increases as the focal length shortens, and it is difficult to compensate aberration.